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Roman Zippel80daa562008-01-14 04:51:16 +01001config ARCH
2 string
3 option env="ARCH"
4
5config KERNELVERSION
6 string
7 option env="KERNELVERSION"
8
Roman Zippelface4372006-06-08 22:12:45 -07009config DEFCONFIG_LIST
10 string
Paolo 'Blaisorblade' Giarrussob2670eac2006-10-19 23:28:23 -070011 depends on !UML
Roman Zippelface4372006-06-08 22:12:45 -070012 option defconfig_list
13 default "/lib/modules/$UNAME_RELEASE/.config"
14 default "/etc/kernel-config"
15 default "/boot/config-$UNAME_RELEASE"
Sam Ravnborg73531902008-05-25 23:03:18 +020016 default "$ARCH_DEFCONFIG"
Roman Zippelface4372006-06-08 22:12:45 -070017 default "arch/$ARCH/defconfig"
18
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -070019config CONSTRUCTORS
20 bool
21 depends on !UML
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -070022
Peter Zijlstrae360adb2010-10-14 14:01:34 +080023config HAVE_IRQ_WORK
24 bool
25
26config IRQ_WORK
27 bool
28 depends on HAVE_IRQ_WORK
29
Al Boldiff0cfc62007-07-31 00:39:23 -070030menu "General setup"
Linus Torvalds1da177e2005-04-16 15:20:36 -070031
32config EXPERIMENTAL
33 bool "Prompt for development and/or incomplete code/drivers"
34 ---help---
35 Some of the various things that Linux supports (such as network
36 drivers, file systems, network protocols, etc.) can be in a state
37 of development where the functionality, stability, or the level of
38 testing is not yet high enough for general use. This is usually
39 known as the "alpha-test" phase among developers. If a feature is
40 currently in alpha-test, then the developers usually discourage
41 uninformed widespread use of this feature by the general public to
42 avoid "Why doesn't this work?" type mail messages. However, active
43 testing and use of these systems is welcomed. Just be aware that it
44 may not meet the normal level of reliability or it may fail to work
45 in some special cases. Detailed bug reports from people familiar
46 with the kernel internals are usually welcomed by the developers
47 (before submitting bug reports, please read the documents
48 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
49 <file:Documentation/BUG-HUNTING>, and
50 <file:Documentation/oops-tracing.txt> in the kernel source).
51
52 This option will also make obsoleted drivers available. These are
53 drivers that have been replaced by something else, and/or are
54 scheduled to be removed in a future kernel release.
55
56 Unless you intend to help test and develop a feature or driver that
57 falls into this category, or you have a situation that requires
58 using these features, you should probably say N here, which will
59 cause the configurator to present you with fewer choices. If
60 you say Y here, you will be offered the choice of using features or
61 drivers that are currently considered to be in the alpha-test phase.
62
Linus Torvalds1da177e2005-04-16 15:20:36 -070063config BROKEN
64 bool
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
66config BROKEN_ON_SMP
67 bool
68 depends on BROKEN || !SMP
69 default y
70
Linus Torvalds1da177e2005-04-16 15:20:36 -070071config INIT_ENV_ARG_LIMIT
72 int
Adrian Bunkdd673bc2006-06-30 01:55:51 -070073 default 32 if !UML
74 default 128 if UML
Linus Torvalds1da177e2005-04-16 15:20:36 -070075 help
Randy Dunlap34ad92c2005-10-30 15:01:46 -080076 Maximum of each of the number of arguments and environment
77 variables passed to init from the kernel command line.
Linus Torvalds1da177e2005-04-16 15:20:36 -070078
Linus Torvalds1da177e2005-04-16 15:20:36 -070079
Roland McGrath84336462009-12-21 16:24:06 -080080config CROSS_COMPILE
81 string "Cross-compiler tool prefix"
82 help
83 Same as running 'make CROSS_COMPILE=prefix-' but stored for
84 default make runs in this kernel build directory. You don't
85 need to set this unless you want the configured kernel build
86 directory to select the cross-compiler automatically.
87
Linus Torvalds1da177e2005-04-16 15:20:36 -070088config LOCALVERSION
89 string "Local version - append to kernel release"
90 help
91 Append an extra string to the end of your kernel version.
92 This will show up when you type uname, for example.
93 The string you set here will be appended after the contents of
94 any files with a filename matching localversion* in your
95 object and source tree, in that order. Your total string can
96 be a maximum of 64 characters.
97
Ryan Andersonaaebf432005-07-31 04:57:49 -040098config LOCALVERSION_AUTO
99 bool "Automatically append version information to the version string"
100 default y
101 help
102 This will try to automatically determine if the current tree is a
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200103 release tree by looking for git tags that belong to the current
104 top of tree revision.
Ryan Andersonaaebf432005-07-31 04:57:49 -0400105
106 A string of the format -gxxxxxxxx will be added to the localversion
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200107 if a git-based tree is found. The string generated by this will be
Ryan Andersonaaebf432005-07-31 04:57:49 -0400108 appended after any matching localversion* files, and after the value
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200109 set in CONFIG_LOCALVERSION.
Ryan Andersonaaebf432005-07-31 04:57:49 -0400110
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200111 (The actual string used here is the first eight characters produced
112 by running the command:
113
114 $ git rev-parse --verify HEAD
115
116 which is done within the script "scripts/setlocalversion".)
Ryan Andersonaaebf432005-07-31 04:57:49 -0400117
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800118config HAVE_KERNEL_GZIP
119 bool
120
121config HAVE_KERNEL_BZIP2
122 bool
123
124config HAVE_KERNEL_LZMA
125 bool
126
Lasse Collin3ebe1242011-01-12 17:01:23 -0800127config HAVE_KERNEL_XZ
128 bool
129
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800130config HAVE_KERNEL_LZO
131 bool
132
Alain Knaff30d65db2009-01-04 22:46:17 +0100133choice
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800134 prompt "Kernel compression mode"
135 default KERNEL_GZIP
Lasse Collin3ebe1242011-01-12 17:01:23 -0800136 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800137 help
Alain Knaff30d65db2009-01-04 22:46:17 +0100138 The linux kernel is a kind of self-extracting executable.
139 Several compression algorithms are available, which differ
140 in efficiency, compression and decompression speed.
141 Compression speed is only relevant when building a kernel.
142 Decompression speed is relevant at each boot.
143
144 If you have any problems with bzip2 or lzma compressed
145 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
146 version of this functionality (bzip2 only), for 2.4, was
147 supplied by Christian Ludwig)
148
149 High compression options are mostly useful for users, who
150 are low on disk space (embedded systems), but for whom ram
151 size matters less.
152
153 If in doubt, select 'gzip'
154
155config KERNEL_GZIP
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800156 bool "Gzip"
157 depends on HAVE_KERNEL_GZIP
158 help
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800159 The old and tried gzip compression. It provides a good balance
160 between compression ratio and decompression speed.
Alain Knaff30d65db2009-01-04 22:46:17 +0100161
162config KERNEL_BZIP2
163 bool "Bzip2"
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800164 depends on HAVE_KERNEL_BZIP2
Alain Knaff30d65db2009-01-04 22:46:17 +0100165 help
166 Its compression ratio and speed is intermediate.
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800167 Decompression speed is slowest among the three. The kernel
168 size is about 10% smaller with bzip2, in comparison to gzip.
169 Bzip2 uses a large amount of memory. For modern kernels you
170 will need at least 8MB RAM or more for booting.
Alain Knaff30d65db2009-01-04 22:46:17 +0100171
172config KERNEL_LZMA
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800173 bool "LZMA"
174 depends on HAVE_KERNEL_LZMA
175 help
176 The most recent compression algorithm.
177 Its ratio is best, decompression speed is between the other
178 two. Compression is slowest. The kernel size is about 33%
179 smaller with LZMA in comparison to gzip.
Alain Knaff30d65db2009-01-04 22:46:17 +0100180
Lasse Collin3ebe1242011-01-12 17:01:23 -0800181config KERNEL_XZ
182 bool "XZ"
183 depends on HAVE_KERNEL_XZ
184 help
185 XZ uses the LZMA2 algorithm and instruction set specific
186 BCJ filters which can improve compression ratio of executable
187 code. The size of the kernel is about 30% smaller with XZ in
188 comparison to gzip. On architectures for which there is a BCJ
189 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
190 will create a few percent smaller kernel than plain LZMA.
191
192 The speed is about the same as with LZMA: The decompression
193 speed of XZ is better than that of bzip2 but worse than gzip
194 and LZO. Compression is slow.
195
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800196config KERNEL_LZO
197 bool "LZO"
198 depends on HAVE_KERNEL_LZO
199 help
200 Its compression ratio is the poorest among the 4. The kernel
Stephan Sperber681b3042010-07-14 11:23:08 +0200201 size is about 10% bigger than gzip; however its speed
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800202 (both compression and decompression) is the fastest.
203
Alain Knaff30d65db2009-01-04 22:46:17 +0100204endchoice
205
Josh Triplettbd5dc172011-06-15 15:08:28 -0700206config DEFAULT_HOSTNAME
207 string "Default hostname"
208 default "(none)"
209 help
210 This option determines the default system hostname before userspace
211 calls sethostname(2). The kernel traditionally uses "(none)" here,
212 but you may wish to use a different default here to make a minimal
213 system more usable with less configuration.
214
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215config SWAP
216 bool "Support for paging of anonymous memory (swap)"
David Howells93614012006-09-30 20:45:40 +0200217 depends on MMU && BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 default y
219 help
220 This option allows you to choose whether you want to have support
Jesper Juhl92c35042006-01-15 02:40:08 +0100221 for so called swap devices or swap files in your kernel that are
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222 used to provide more virtual memory than the actual RAM present
223 in your computer. If unsure say Y.
224
225config SYSVIPC
226 bool "System V IPC"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 ---help---
228 Inter Process Communication is a suite of library functions and
229 system calls which let processes (running programs) synchronize and
230 exchange information. It is generally considered to be a good thing,
231 and some programs won't run unless you say Y here. In particular, if
232 you want to run the DOS emulator dosemu under Linux (read the
233 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
234 you'll need to say Y here.
235
236 You can find documentation about IPC with "info ipc" and also in
237 section 6.4 of the Linux Programmer's Guide, available from
238 <http://www.tldp.org/guides.html>.
239
Eric W. Biedermana5494dc2007-02-14 00:34:06 -0800240config SYSVIPC_SYSCTL
241 bool
242 depends on SYSVIPC
243 depends on SYSCTL
244 default y
245
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246config POSIX_MQUEUE
247 bool "POSIX Message Queues"
248 depends on NET && EXPERIMENTAL
249 ---help---
250 POSIX variant of message queues is a part of IPC. In POSIX message
251 queues every message has a priority which decides about succession
252 of receiving it by a process. If you want to compile and run
253 programs written e.g. for Solaris with use of its POSIX message
Robert P. J. Dayb0e37652007-05-09 07:25:13 +0200254 queues (functions mq_*) say Y here.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255
256 POSIX message queues are visible as a filesystem called 'mqueue'
257 and can be mounted somewhere if you want to do filesystem
258 operations on message queues.
259
260 If unsure, say Y.
261
Serge E. Hallynbdc8e5f2009-04-06 19:01:11 -0700262config POSIX_MQUEUE_SYSCTL
263 bool
264 depends on POSIX_MQUEUE
265 depends on SYSCTL
266 default y
267
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268config BSD_PROCESS_ACCT
269 bool "BSD Process Accounting"
270 help
271 If you say Y here, a user level program will be able to instruct the
272 kernel (via a special system call) to write process accounting
273 information to a file: whenever a process exits, information about
274 that process will be appended to the file by the kernel. The
275 information includes things such as creation time, owning user,
276 command name, memory usage, controlling terminal etc. (the complete
277 list is in the struct acct in <file:include/linux/acct.h>). It is
278 up to the user level program to do useful things with this
279 information. This is generally a good idea, so say Y.
280
281config BSD_PROCESS_ACCT_V3
282 bool "BSD Process Accounting version 3 file format"
283 depends on BSD_PROCESS_ACCT
284 default n
285 help
286 If you say Y here, the process accounting information is written
287 in a new file format that also logs the process IDs of each
288 process and it's parent. Note that this file format is incompatible
289 with previous v0/v1/v2 file formats, so you will need updated tools
290 for processing it. A preliminary version of these tools is available
S.Çağlar Onur37a4c942008-06-18 11:45:13 +0300291 at <http://www.gnu.org/software/acct/>.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292
Aneesh Kumar K.V990d6c22011-01-29 18:43:26 +0530293config FHANDLE
294 bool "open by fhandle syscalls"
295 select EXPORTFS
296 help
297 If you say Y here, a user level program will be able to map
298 file names to handle and then later use the handle for
299 different file system operations. This is useful in implementing
300 userspace file servers, which now track files using handles instead
301 of names. The handle would remain the same even if file names
302 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
303 syscalls.
304
Shailabh Nagarc7572492006-07-14 00:24:40 -0700305config TASKSTATS
306 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
307 depends on NET
308 default n
309 help
310 Export selected statistics for tasks/processes through the
311 generic netlink interface. Unlike BSD process accounting, the
312 statistics are available during the lifetime of tasks/processes as
313 responses to commands. Like BSD accounting, they are sent to user
314 space on task exit.
315
316 Say N if unsure.
317
Shailabh Nagarca74e922006-07-14 00:24:36 -0700318config TASK_DELAY_ACCT
319 bool "Enable per-task delay accounting (EXPERIMENTAL)"
Shailabh Nagar6f449932006-07-14 00:24:41 -0700320 depends on TASKSTATS
Shailabh Nagarca74e922006-07-14 00:24:36 -0700321 help
322 Collect information on time spent by a task waiting for system
323 resources like cpu, synchronous block I/O completion and swapping
324 in pages. Such statistics can help in setting a task's priorities
325 relative to other tasks for cpu, io, rss limits etc.
326
327 Say N if unsure.
328
Alexey Dobriyan18f705f2007-02-10 01:46:44 -0800329config TASK_XACCT
330 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
331 depends on TASKSTATS
332 help
333 Collect extended task accounting data and send the data
334 to userland for processing over the taskstats interface.
335
336 Say N if unsure.
337
338config TASK_IO_ACCOUNTING
339 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
340 depends on TASK_XACCT
341 help
342 Collect information on the number of bytes of storage I/O which this
343 task has caused.
344
345 Say N if unsure.
346
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347config AUDIT
348 bool "Auditing support"
Chris Wright804a6a492005-05-11 10:52:45 +0100349 depends on NET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 help
351 Enable auditing infrastructure that can be used with another
352 kernel subsystem, such as SELinux (which requires this for
353 logging of avc messages output). Does not do system-call
354 auditing without CONFIG_AUDITSYSCALL.
355
356config AUDITSYSCALL
357 bool "Enable system-call auditing support"
Nathaniel Husted29ef73b2012-01-03 14:23:09 -0500358 depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || ARM)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 default y if SECURITY_SELINUX
360 help
361 Enable low-overhead system-call auditing infrastructure that
362 can be used independently or with another kernel subsystem,
Eric Paris67640b62009-12-17 20:12:06 -0500363 such as SELinux.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364
Eric Paris939a67f2009-12-17 20:12:06 -0500365config AUDIT_WATCH
366 def_bool y
367 depends on AUDITSYSCALL
368 select FSNOTIFY
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369
Al Viro74c3cbe2007-07-22 08:04:18 -0400370config AUDIT_TREE
371 def_bool y
Eric Paris63c882a2009-05-21 17:02:01 -0400372 depends on AUDITSYSCALL
Eric Paris28a3a7e2009-12-17 20:12:05 -0500373 select FSNOTIFY
Al Viro74c3cbe2007-07-22 08:04:18 -0400374
Eric Paris633b4542012-01-03 14:23:08 -0500375config AUDIT_LOGINUID_IMMUTABLE
376 bool "Make audit loginuid immutable"
377 depends on AUDIT
378 help
379 The config option toggles if a task setting it's loginuid requires
380 CAP_SYS_AUDITCONTROL or if that task should require no special permissions
381 but should instead only allow setting its loginuid if it was never
382 previously set. On systems which use systemd or a similar central
383 process to restart login services this should be set to true. On older
384 systems in which an admin would typically have to directly stop and
385 start processes this should be set to false. Setting this to true allows
386 one to drop potentially dangerous capabilites from the login tasks,
387 but may not be backwards compatible with older init systems.
388
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000389source "kernel/irq/Kconfig"
390
Mike Travisc903ff82009-01-15 12:28:29 -0800391menu "RCU Subsystem"
392
393choice
394 prompt "RCU Implementation"
Paul E. McKenney31c9a242009-04-02 21:06:25 -0700395 default TREE_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800396
Mike Travisc903ff82009-01-15 12:28:29 -0800397config TREE_RCU
398 bool "Tree-based hierarchical RCU"
Paul E. McKenney687d7a92010-07-21 06:52:40 -0700399 depends on !PREEMPT && SMP
Mike Travisc903ff82009-01-15 12:28:29 -0800400 help
401 This option selects the RCU implementation that is
402 designed for very large SMP system with hundreds or
Paul E. McKenneyc17ef452009-06-23 17:12:47 -0700403 thousands of CPUs. It also scales down nicely to
404 smaller systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800405
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700406config TREE_PREEMPT_RCU
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700407 bool "Preemptible tree-based hierarchical RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700408 depends on PREEMPT && SMP
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700409 help
410 This option selects the RCU implementation that is
411 designed for very large SMP systems with hundreds or
412 thousands of CPUs, but for which real-time response
Paul E. McKenneybbe3eae2009-09-13 09:15:08 -0700413 is also required. It also scales down nicely to
414 smaller systems.
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700415
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700416config TINY_RCU
417 bool "UP-only small-memory-footprint RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700418 depends on !PREEMPT && !SMP
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700419 help
420 This option selects the RCU implementation that is
421 designed for UP systems from which real-time response
422 is not required. This option greatly reduces the
423 memory footprint of RCU.
424
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700425config TINY_PREEMPT_RCU
426 bool "Preemptible UP-only small-memory-footprint RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700427 depends on PREEMPT && !SMP
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700428 help
429 This option selects the RCU implementation that is designed
430 for real-time UP systems. This option greatly reduces the
431 memory footprint of RCU.
432
Mike Travisc903ff82009-01-15 12:28:29 -0800433endchoice
434
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700435config PREEMPT_RCU
436 def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
437 help
438 This option enables preemptible-RCU code that is common between
439 the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
440
Mike Travisc903ff82009-01-15 12:28:29 -0800441config RCU_TRACE
442 bool "Enable tracing for RCU"
Mike Travisc903ff82009-01-15 12:28:29 -0800443 help
444 This option provides tracing in RCU which presents stats
445 in debugfs for debugging RCU implementation.
446
447 Say Y here if you want to enable RCU tracing
448 Say N if you are unsure.
449
450config RCU_FANOUT
451 int "Tree-based hierarchical RCU fanout value"
452 range 2 64 if 64BIT
453 range 2 32 if !64BIT
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700454 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800455 default 64 if 64BIT
456 default 32 if !64BIT
457 help
458 This option controls the fanout of hierarchical implementations
459 of RCU, allowing RCU to work efficiently on machines with
Paul E. McKenney4d87ffa2010-08-04 17:31:12 -0700460 large numbers of CPUs. This value must be at least the fourth
461 root of NR_CPUS, which allows NR_CPUS to be insanely large.
462 The default value of RCU_FANOUT should be used for production
463 systems, but if you are stress-testing the RCU implementation
464 itself, small RCU_FANOUT values allow you to test large-system
465 code paths on small(er) systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800466
467 Select a specific number if testing RCU itself.
468 Take the default if unsure.
469
470config RCU_FANOUT_EXACT
471 bool "Disable tree-based hierarchical RCU auto-balancing"
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700472 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800473 default n
474 help
475 This option forces use of the exact RCU_FANOUT value specified,
476 regardless of imbalances in the hierarchy. This is useful for
477 testing RCU itself, and might one day be useful on systems with
478 strong NUMA behavior.
479
480 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
481
482 Say N if unsure.
483
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800484config RCU_FAST_NO_HZ
485 bool "Accelerate last non-dyntick-idle CPU's grace periods"
Paul E. McKenneyb807fbf2011-11-03 14:56:12 -0700486 depends on NO_HZ && SMP
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800487 default n
488 help
489 This option causes RCU to attempt to accelerate grace periods
Paul E. McKenneyb807fbf2011-11-03 14:56:12 -0700490 in order to allow CPUs to enter dynticks-idle state more
491 quickly. On the other hand, this option increases the overhead
492 of the dynticks-idle checking, particularly on systems with
493 large numbers of CPUs.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800494
495 Say Y if energy efficiency is critically important, particularly
496 if you have relatively few CPUs.
497
498 Say N if you are unsure.
499
Mike Travisc903ff82009-01-15 12:28:29 -0800500config TREE_RCU_TRACE
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700501 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800502 select DEBUG_FS
503 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700504 This option provides tracing for the TREE_RCU and
505 TREE_PREEMPT_RCU implementations, permitting Makefile to
506 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800507
Paul E. McKenney24278d12010-09-27 17:25:23 -0700508config RCU_BOOST
509 bool "Enable RCU priority boosting"
Paul E. McKenney27f4d282011-02-07 12:47:15 -0800510 depends on RT_MUTEXES && PREEMPT_RCU
Paul E. McKenney24278d12010-09-27 17:25:23 -0700511 default n
512 help
513 This option boosts the priority of preempted RCU readers that
514 block the current preemptible RCU grace period for too long.
515 This option also prevents heavy loads from blocking RCU
516 callback invocation for all flavors of RCU.
517
518 Say Y here if you are working with real-time apps or heavy loads
519 Say N here if you are unsure.
520
521config RCU_BOOST_PRIO
522 int "Real-time priority to boost RCU readers to"
523 range 1 99
524 depends on RCU_BOOST
525 default 1
526 help
527 This option specifies the real-time priority to which preempted
528 RCU readers are to be boosted. If you are working with CPU-bound
529 real-time applications, you should specify a priority higher then
530 the highest-priority CPU-bound application.
531
532 Specify the real-time priority, or take the default if unsure.
533
534config RCU_BOOST_DELAY
535 int "Milliseconds to delay boosting after RCU grace-period start"
536 range 0 3000
537 depends on RCU_BOOST
538 default 500
539 help
540 This option specifies the time to wait after the beginning of
541 a given grace period before priority-boosting preempted RCU
542 readers blocking that grace period. Note that any RCU reader
543 blocking an expedited RCU grace period is boosted immediately.
544
545 Accept the default if unsure.
546
Mike Travisc903ff82009-01-15 12:28:29 -0800547endmenu # "RCU Subsystem"
548
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700550 tristate "Kernel .config support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 ---help---
552 This option enables the complete Linux kernel ".config" file
553 contents to be saved in the kernel. It provides documentation
554 of which kernel options are used in a running kernel or in an
555 on-disk kernel. This information can be extracted from the kernel
556 image file with the script scripts/extract-ikconfig and used as
557 input to rebuild the current kernel or to build another kernel.
558 It can also be extracted from a running kernel by reading
559 /proc/config.gz if enabled (below).
560
561config IKCONFIG_PROC
562 bool "Enable access to .config through /proc/config.gz"
563 depends on IKCONFIG && PROC_FS
564 ---help---
565 This option enables access to the kernel configuration file
566 through /proc/config.gz.
567
Alistair John Strachan794543a2007-05-08 00:31:15 -0700568config LOG_BUF_SHIFT
569 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
570 range 12 21
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700571 default 17
Alistair John Strachan794543a2007-05-08 00:31:15 -0700572 help
573 Select kernel log buffer size as a power of 2.
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700574 Examples:
575 17 => 128 KB
576 16 => 64 KB
577 15 => 32 KB
578 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700579 13 => 8 KB
580 12 => 4 KB
581
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800582#
583# Architectures with an unreliable sched_clock() should select this:
584#
585config HAVE_UNSTABLE_SCHED_CLOCK
586 bool
587
Li Zefan23964d22009-01-15 13:50:58 -0800588menuconfig CGROUPS
589 boolean "Control Group support"
Kirill A. Shutemov0dea1162010-03-10 15:22:20 -0800590 depends on EVENTFD
Paul Menageddbcc7e2007-10-18 23:39:30 -0700591 help
Li Zefan23964d22009-01-15 13:50:58 -0800592 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800593 use with process control subsystems such as Cpusets, CFS, memory
594 controls or device isolation.
595 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800596 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800597 - Documentation/cgroups/ (features for grouping, isolation
598 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700599
600 Say N if unsure.
601
Li Zefan23964d22009-01-15 13:50:58 -0800602if CGROUPS
603
Paul Menage006cb992007-10-18 23:39:43 -0700604config CGROUP_DEBUG
605 bool "Example debug cgroup subsystem"
Paul Menage418d7d82008-04-29 01:00:05 -0700606 default n
Paul Menage006cb992007-10-18 23:39:43 -0700607 help
608 This option enables a simple cgroup subsystem that
609 exports useful debugging information about the cgroups
Li Zefan23964d22009-01-15 13:50:58 -0800610 framework.
Paul Menage006cb992007-10-18 23:39:43 -0700611
Li Zefan23964d22009-01-15 13:50:58 -0800612 Say N if unsure.
Paul Menage006cb992007-10-18 23:39:43 -0700613
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700614config CGROUP_FREEZER
Li Zefan23964d22009-01-15 13:50:58 -0800615 bool "Freezer cgroup subsystem"
Li Zefan23964d22009-01-15 13:50:58 -0800616 help
617 Provides a way to freeze and unfreeze all tasks in a
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700618 cgroup.
619
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700620config CGROUP_DEVICE
621 bool "Device controller for cgroups"
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700622 help
623 Provides a cgroup implementing whitelists for devices which
624 a process in the cgroup can mknod or open.
625
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626config CPUSETS
627 bool "Cpuset support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700628 help
Randy Dunlapd9fd8a62005-07-27 11:45:11 -0700629 This option will let you create and manage CPUSETs which
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630 allow dynamically partitioning a system into sets of CPUs and
631 Memory Nodes and assigning tasks to run only within those sets.
632 This is primarily useful on large SMP or NUMA systems.
633
634 Say N if unsure.
635
Li Zefan23964d22009-01-15 13:50:58 -0800636config PROC_PID_CPUSET
637 bool "Include legacy /proc/<pid>/cpuset file"
638 depends on CPUSETS
639 default y
640
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100641config CGROUP_CPUACCT
642 bool "Simple CPU accounting cgroup subsystem"
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100643 help
644 Provides a simple Resource Controller for monitoring the
Li Zefan23964d22009-01-15 13:50:58 -0800645 total CPU consumed by the tasks in a cgroup.
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100646
Pavel Emelianove552b662008-02-07 00:13:49 -0800647config RESOURCE_COUNTERS
648 bool "Resource counters"
649 help
650 This option enables controller independent resource accounting
Li Zefan23964d22009-01-15 13:50:58 -0800651 infrastructure that works with cgroups.
Pavel Emelianove552b662008-02-07 00:13:49 -0800652
Balbir Singh00f0b822008-03-04 14:28:39 -0800653config CGROUP_MEM_RES_CTLR
654 bool "Memory Resource Controller for Control Groups"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -0700655 depends on RESOURCE_COUNTERS
Balbir Singhcf475ad2008-04-29 01:00:16 -0700656 select MM_OWNER
Balbir Singh00f0b822008-03-04 14:28:39 -0800657 help
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700658 Provides a memory resource controller that manages both anonymous
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +0100659 memory and page cache. (See Documentation/cgroups/memory.txt)
Balbir Singh00f0b822008-03-04 14:28:39 -0800660
661 Note that setting this option increases fixed memory overhead
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700662 associated with each page of memory in the system. By this,
663 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
664 usage tracking struct at boot. Total amount of this is printed out
665 at boot.
Balbir Singh00f0b822008-03-04 14:28:39 -0800666
667 Only enable when you're ok with these trade offs and really
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700668 sure you need the memory resource controller. Even when you enable
669 this, you can set "cgroup_disable=memory" at your boot option to
670 disable memory resource controller and you can avoid overheads.
Li Zefanc9d54092009-01-07 18:07:35 -0800671 (and lose benefits of memory resource controller)
Balbir Singh00f0b822008-03-04 14:28:39 -0800672
Balbir Singhcf475ad2008-04-29 01:00:16 -0700673 This config option also selects MM_OWNER config option, which
674 could in turn add some fork/exit overhead.
675
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800676config CGROUP_MEM_RES_CTLR_SWAP
KAMEZAWA Hiroyuki65e0e812010-08-10 18:02:56 -0700677 bool "Memory Resource Controller Swap Extension"
678 depends on CGROUP_MEM_RES_CTLR && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800679 help
680 Add swap management feature to memory resource controller. When you
681 enable this, you can limit mem+swap usage per cgroup. In other words,
682 when you disable this, memory resource controller has no cares to
683 usage of swap...a process can exhaust all of the swap. This extension
684 is useful when you want to avoid exhaustion swap but this itself
685 adds more overheads and consumes memory for remembering information.
686 Especially if you use 32bit system or small memory system, please
687 be careful about enabling this. When memory resource controller
688 is disabled by boot option, this will be automatically disabled and
689 there will be no overhead from this. Even when you set this config=y,
WANG Cong00a66d22011-07-25 17:12:12 -0700690 if boot option "swapaccount=0" is set, swap will not be accounted.
KAMEZAWA Hiroyuki627991a2009-04-02 16:57:47 -0700691 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
692 size is 4096bytes, 512k per 1Gbytes of swap.
Michal Hockoa42c3902010-11-24 12:57:08 -0800693config CGROUP_MEM_RES_CTLR_SWAP_ENABLED
694 bool "Memory Resource Controller Swap Extension enabled by default"
695 depends on CGROUP_MEM_RES_CTLR_SWAP
696 default y
697 help
698 Memory Resource Controller Swap Extension comes with its price in
699 a bigger memory consumption. General purpose distribution kernels
Jim Cromie43d547f2010-12-17 14:32:36 -0700700 which want to enable the feature but keep it disabled by default
Michal Hockoa42c3902010-11-24 12:57:08 -0800701 and let the user enable it by swapaccount boot command line
702 parameter should have this option unselected.
703 For those who want to have the feature enabled by default should
704 select this option (if, for some reason, they need to disable it
WANG Cong00a66d22011-07-25 17:12:12 -0700705 then swapaccount=0 does the trick).
Glauber Costae5671df2011-12-11 21:47:01 +0000706config CGROUP_MEM_RES_CTLR_KMEM
707 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
708 depends on CGROUP_MEM_RES_CTLR && EXPERIMENTAL
709 default n
710 help
711 The Kernel Memory extension for Memory Resource Controller can limit
712 the amount of memory used by kernel objects in the system. Those are
713 fundamentally different from the entities handled by the standard
714 Memory Controller, which are page-based, and can be swapped. Users of
715 the kmem extension can use it to guarantee that no group of processes
716 will ever exhaust kernel resources alone.
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800717
Stephane Eraniane5d13672011-02-14 11:20:01 +0200718config CGROUP_PERF
719 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
720 depends on PERF_EVENTS && CGROUPS
721 help
722 This option extends the per-cpu mode to restrict monitoring to
Li Zefan2d0f2522011-03-03 14:26:20 +0800723 threads which belong to the cgroup specified and run on the
Stephane Eraniane5d13672011-02-14 11:20:01 +0200724 designated cpu.
725
726 Say N if unsure.
727
Dhaval Giani7c941432010-01-20 13:26:18 +0100728menuconfig CGROUP_SCHED
729 bool "Group CPU scheduler"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -0700730 depends on EXPERIMENTAL
Dhaval Giani7c941432010-01-20 13:26:18 +0100731 default n
732 help
733 This feature lets CPU scheduler recognize task groups and control CPU
734 bandwidth allocation to such task groups. It uses cgroups to group
735 tasks.
736
737if CGROUP_SCHED
738config FAIR_GROUP_SCHED
739 bool "Group scheduling for SCHED_OTHER"
740 depends on CGROUP_SCHED
741 default CGROUP_SCHED
742
Paul Turnerab84d312011-07-21 09:43:28 -0700743config CFS_BANDWIDTH
744 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
745 depends on EXPERIMENTAL
746 depends on FAIR_GROUP_SCHED
747 default n
748 help
749 This option allows users to define CPU bandwidth rates (limits) for
750 tasks running within the fair group scheduler. Groups with no limit
751 set are considered to be unconstrained and will run with no
752 restriction.
753 See tip/Documentation/scheduler/sched-bwc.txt for more information.
754
Dhaval Giani7c941432010-01-20 13:26:18 +0100755config RT_GROUP_SCHED
756 bool "Group scheduling for SCHED_RR/FIFO"
757 depends on EXPERIMENTAL
758 depends on CGROUP_SCHED
759 default n
760 help
761 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +0800762 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +0100763 schedule realtime tasks for non-root users until you allocate
764 realtime bandwidth for them.
765 See Documentation/scheduler/sched-rt-group.txt for more information.
766
767endif #CGROUP_SCHED
768
Vivek Goyalafc24d42010-04-26 19:27:56 +0200769config BLK_CGROUP
770 tristate "Block IO controller"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -0700771 depends on BLOCK
Vivek Goyalafc24d42010-04-26 19:27:56 +0200772 default n
773 ---help---
774 Generic block IO controller cgroup interface. This is the common
775 cgroup interface which should be used by various IO controlling
776 policies.
777
778 Currently, CFQ IO scheduler uses it to recognize task groups and
779 control disk bandwidth allocation (proportional time slice allocation)
Vivek Goyale43473b2010-09-15 17:06:35 -0400780 to such task groups. It is also used by bio throttling logic in
781 block layer to implement upper limit in IO rates on a device.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200782
783 This option only enables generic Block IO controller infrastructure.
Vivek Goyale43473b2010-09-15 17:06:35 -0400784 One needs to also enable actual IO controlling logic/policy. For
Michael Witten79e2e752011-01-16 21:43:10 +0000785 enabling proportional weight division of disk bandwidth in CFQ, set
786 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
Michael Wittenc5e05912011-01-17 00:08:41 +0000787 CONFIG_BLK_DEV_THROTTLING=y.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200788
789 See Documentation/cgroups/blkio-controller.txt for more information.
790
791config DEBUG_BLK_CGROUP
792 bool "Enable Block IO controller debugging"
793 depends on BLK_CGROUP
794 default n
795 ---help---
796 Enable some debugging help. Currently it exports additional stat
797 files in a cgroup which can be useful for debugging.
798
Li Zefan23964d22009-01-15 13:50:58 -0800799endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800800
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700801menuconfig NAMESPACES
David Rientjes6a108a12011-01-20 14:44:16 -0800802 bool "Namespaces support" if EXPERT
803 default !EXPERT
Pavel Emelyanovc5289a62008-02-08 04:18:19 -0800804 help
805 Provides the way to make tasks work with different objects using
806 the same id. For example same IPC id may refer to different objects
807 or same user id or pid may refer to different tasks when used in
808 different namespaces.
809
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700810if NAMESPACES
811
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -0800812config UTS_NS
813 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700814 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -0800815 help
816 In this namespace tasks see different info provided with the
817 uname() system call
818
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800819config IPC_NS
820 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700821 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700822 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800823 help
824 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -0700825 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800826
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -0800827config USER_NS
828 bool "User namespace (EXPERIMENTAL)"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700829 depends on EXPERIMENTAL
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700830 default y
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -0800831 help
832 This allows containers, i.e. vservers, to use user namespaces
833 to provide different user info for different servers.
834 If unsure, say N.
835
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800836config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -0700837 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700838 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800839 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +0300840 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +0100841 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800842 pid namespaces. This is a building block of containers.
843
Matt Helsleyd6eb6332009-01-26 12:25:55 -0800844config NET_NS
845 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700846 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700847 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -0800848 help
849 Allow user space to create what appear to be multiple instances
850 of the network stack.
851
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700852endif # NAMESPACES
853
Mike Galbraith5091faa2010-11-30 14:18:03 +0100854config SCHED_AUTOGROUP
855 bool "Automatic process group scheduling"
856 select EVENTFD
857 select CGROUPS
858 select CGROUP_SCHED
859 select FAIR_GROUP_SCHED
860 help
861 This option optimizes the scheduler for common desktop workloads by
862 automatically creating and populating task groups. This separation
863 of workloads isolates aggressive CPU burners (like build jobs) from
864 desktop applications. Task group autogeneration is currently based
865 upon task session.
866
Daniel Lezcano7af37be2010-10-27 15:34:41 -0700867config MM_OWNER
868 bool
869
870config SYSFS_DEPRECATED
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +0100871 bool "Enable deprecated sysfs features to support old userspace tools"
Daniel Lezcano7af37be2010-10-27 15:34:41 -0700872 depends on SYSFS
873 default n
874 help
875 This option adds code that switches the layout of the "block" class
876 devices, to not show up in /sys/class/block/, but only in
877 /sys/block/.
878
879 This switch is only active when the sysfs.deprecated=1 boot option is
880 passed or the SYSFS_DEPRECATED_V2 option is set.
881
882 This option allows new kernels to run on old distributions and tools,
883 which might get confused by /sys/class/block/. Since 2007/2008 all
884 major distributions and tools handle this just fine.
885
886 Recent distributions and userspace tools after 2009/2010 depend on
887 the existence of /sys/class/block/, and will not work with this
888 option enabled.
889
890 Only if you are using a new kernel on an old distribution, you might
891 need to say Y here.
892
893config SYSFS_DEPRECATED_V2
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +0100894 bool "Enable deprecated sysfs features by default"
Daniel Lezcano7af37be2010-10-27 15:34:41 -0700895 default n
896 depends on SYSFS
897 depends on SYSFS_DEPRECATED
898 help
899 Enable deprecated sysfs by default.
900
901 See the CONFIG_SYSFS_DEPRECATED option for more details about this
902 option.
903
904 Only if you are using a new kernel on an old distribution, you might
905 need to say Y here. Even then, odds are you would not need it
906 enabled, you can always pass the boot option if absolutely necessary.
907
908config RELAY
909 bool "Kernel->user space relay support (formerly relayfs)"
910 help
911 This option enables support for relay interface support in
912 certain file systems (such as debugfs).
913 It is designed to provide an efficient mechanism for tools and
914 facilities to relay large amounts of data from kernel space to
915 user space.
916
917 If unsure, say N.
918
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -0800919config BLK_DEV_INITRD
920 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
921 depends on BROKEN || !FRV
922 help
923 The initial RAM filesystem is a ramfs which is loaded by the
924 boot loader (loadlin or lilo) and that is mounted as root
925 before the normal boot procedure. It is typically used to
926 load modules needed to mount the "real" root file system,
927 etc. See <file:Documentation/initrd.txt> for details.
928
929 If RAM disk support (BLK_DEV_RAM) is also included, this
930 also enables initial RAM disk (initrd) support and adds
931 15 Kbytes (more on some other architectures) to the kernel size.
932
933 If unsure say Y.
934
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -0800935if BLK_DEV_INITRD
936
Sam Ravnborgdbec4862005-08-10 20:44:50 +0200937source "usr/Kconfig"
938
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -0800939endif
940
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800941config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +0200942 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800943 help
944 Enabling this option will pass "-Os" instead of "-O2" to gcc
945 resulting in a smaller kernel.
946
jkacur775a7222008-07-16 00:31:16 +0200947 If unsure, say Y.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800948
Randy Dunlap08470622006-09-30 23:28:13 -0700949config SYSCTL
950 bool
951
Randy Dunlapb943c462009-03-10 12:55:46 -0700952config ANON_INODES
953 bool
954
David Rientjes6a108a12011-01-20 14:44:16 -0800955menuconfig EXPERT
956 bool "Configure standard kernel features (expert users)"
Josh Triplettf505c552011-06-05 18:23:58 -0700957 # Unhide debug options, to make the on-by-default options visible
958 select DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959 help
960 This option allows certain base kernel options and settings
961 to be disabled or tweaked. This is for specialized
962 environments which can tolerate a "non-standard" kernel.
963 Only use this if you really know what you are doing.
964
Chuck Ebbertae81f9e2006-09-16 12:15:53 -0700965config UID16
David Rientjes6a108a12011-01-20 14:44:16 -0800966 bool "Enable 16-bit UID system calls" if EXPERT
David S. Miller09337f52008-04-26 03:17:12 -0700967 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
Chuck Ebbertae81f9e2006-09-16 12:15:53 -0700968 default y
969 help
970 This enables the legacy 16-bit UID syscall wrappers.
971
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700972config SYSCTL_SYSCALL
David Rientjes6a108a12011-01-20 14:44:16 -0800973 bool "Sysctl syscall support" if EXPERT
Eric W. Biederman26a70342009-11-05 05:26:41 -0800974 depends on PROC_SYSCTL
WANG Congc736de62011-11-02 13:39:25 -0700975 default n
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700976 select SYSCTL
977 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800978 sys_sysctl uses binary paths that have been found challenging
979 to properly maintain and use. The interface in /proc/sys
980 using paths with ascii names is now the primary path to this
981 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700982
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800983 Almost nothing using the binary sysctl interface so if you are
984 trying to save some space it is probably safe to disable this,
985 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700986
WANG Congc736de62011-11-02 13:39:25 -0700987 If unsure say N here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -0700988
Linus Torvalds1da177e2005-04-16 15:20:36 -0700989config KALLSYMS
David Rientjes6a108a12011-01-20 14:44:16 -0800990 bool "Load all symbols for debugging/ksymoops" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700991 default y
992 help
993 Say Y here to let the kernel print out symbolic crash information and
994 symbolic stack backtraces. This increases the size of the kernel
995 somewhat, as all symbols have to be loaded into the kernel image.
996
997config KALLSYMS_ALL
998 bool "Include all symbols in kallsyms"
999 depends on DEBUG_KERNEL && KALLSYMS
1000 help
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001001 Normally kallsyms only contains the symbols of functions for nicer
1002 OOPS messages and backtraces (i.e., symbols from the text and inittext
1003 sections). This is sufficient for most cases. And only in very rare
1004 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1005 names of variables from the data sections, etc).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001006
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001007 This option makes sure that all symbols are loaded into the kernel
1008 image (i.e., symbols from all sections) in cost of increased kernel
1009 size (depending on the kernel configuration, it may be 300KiB or
1010 something like this).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001012 Say N unless you really need all symbols.
Matt Mackalld59745c2005-05-01 08:59:02 -07001013
Greg Kroah-Hartman712f47c2005-11-16 11:27:07 -08001014config HOTPLUG
David Rientjes6a108a12011-01-20 14:44:16 -08001015 bool "Support for hot-pluggable devices" if EXPERT
Greg Kroah-Hartman712f47c2005-11-16 11:27:07 -08001016 default y
1017 help
1018 This option is provided for the case where no hotplug or uevent
1019 capabilities is wanted by the kernel. You should only consider
1020 disabling this option for embedded systems that do not use modules, a
1021 dynamic /dev tree, or dynamic device discovery. Just say Y.
1022
Matt Mackalld59745c2005-05-01 08:59:02 -07001023config PRINTK
1024 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001025 bool "Enable support for printk" if EXPERT
Matt Mackalld59745c2005-05-01 08:59:02 -07001026 help
1027 This option enables normal printk support. Removing it
1028 eliminates most of the message strings from the kernel image
1029 and makes the kernel more or less silent. As this makes it
1030 very difficult to diagnose system problems, saying N here is
1031 strongly discouraged.
1032
Matt Mackallc8538a72005-05-01 08:59:01 -07001033config BUG
David Rientjes6a108a12011-01-20 14:44:16 -08001034 bool "BUG() support" if EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -07001035 default y
1036 help
1037 Disabling this option eliminates support for BUG and WARN, reducing
1038 the size of your kernel image and potentially quietly ignoring
1039 numerous fatal conditions. You should only consider disabling this
1040 option for embedded systems with no facilities for reporting errors.
1041 Just say Y.
1042
Matt Mackall708e9a72006-01-08 01:05:25 -08001043config ELF_CORE
1044 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001045 bool "Enable ELF core dumps" if EXPERT
Matt Mackall708e9a72006-01-08 01:05:25 -08001046 help
1047 Enable support for generating core dumps. Disabling saves about 4k.
1048
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001049
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001050config PCSPKR_PLATFORM
David Rientjes6a108a12011-01-20 14:44:16 -08001051 bool "Enable PC-Speaker support" if EXPERT
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001052 depends on HAVE_PCSPKR_PLATFORM
Ralf Baechle15f304b2011-06-01 19:04:59 +01001053 select I8253_LOCK
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001054 default y
1055 help
1056 This option allows to disable the internal PC-Speaker
1057 support, saving some memory.
1058
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001059config HAVE_PCSPKR_PLATFORM
1060 bool
1061
Linus Torvalds1da177e2005-04-16 15:20:36 -07001062config BASE_FULL
1063 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001064 bool "Enable full-sized data structures for core" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001065 help
1066 Disabling this option reduces the size of miscellaneous core
1067 kernel data structures. This saves memory on small machines,
1068 but may reduce performance.
1069
1070config FUTEX
David Rientjes6a108a12011-01-20 14:44:16 -08001071 bool "Enable futex support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001072 default y
Ingo Molnar23f78d4a2006-06-27 02:54:53 -07001073 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074 help
1075 Disabling this option will cause the kernel to be built without
1076 support for "fast userspace mutexes". The resulting kernel may not
1077 run glibc-based applications correctly.
1078
1079config EPOLL
David Rientjes6a108a12011-01-20 14:44:16 -08001080 bool "Enable eventpoll support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001081 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001082 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001083 help
1084 Disabling this option will cause the kernel to be built without
1085 support for epoll family of system calls.
1086
Davide Libenzifba2afa2007-05-10 22:23:13 -07001087config SIGNALFD
David Rientjes6a108a12011-01-20 14:44:16 -08001088 bool "Enable signalfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001089 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -07001090 default y
1091 help
1092 Enable the signalfd() system call that allows to receive signals
1093 on a file descriptor.
1094
1095 If unsure, say Y.
1096
Davide Libenzib215e282007-05-10 22:23:16 -07001097config TIMERFD
David Rientjes6a108a12011-01-20 14:44:16 -08001098 bool "Enable timerfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001099 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -07001100 default y
1101 help
1102 Enable the timerfd() system call that allows to receive timer
1103 events on a file descriptor.
1104
1105 If unsure, say Y.
1106
Davide Libenzie1ad7462007-05-10 22:23:19 -07001107config EVENTFD
David Rientjes6a108a12011-01-20 14:44:16 -08001108 bool "Enable eventfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001109 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -07001110 default y
1111 help
1112 Enable the eventfd() system call that allows to receive both
1113 kernel notification (ie. KAIO) or userspace notifications.
1114
1115 If unsure, say Y.
1116
Linus Torvalds1da177e2005-04-16 15:20:36 -07001117config SHMEM
David Rientjes6a108a12011-01-20 14:44:16 -08001118 bool "Use full shmem filesystem" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001119 default y
1120 depends on MMU
1121 help
1122 The shmem is an internal filesystem used to manage shared memory.
1123 It is backed by swap and manages resource limits. It is also exported
1124 to userspace as tmpfs if TMPFS is enabled. Disabling this
1125 option replaces shmem and tmpfs with the much simpler ramfs code,
1126 which may be appropriate on small systems without swap.
1127
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001128config AIO
David Rientjes6a108a12011-01-20 14:44:16 -08001129 bool "Enable AIO support" if EXPERT
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001130 default y
1131 help
1132 This option enables POSIX asynchronous I/O which may by used
1133 by some high performance threaded applications. Disabling
1134 this option saves about 7k.
1135
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001136config EMBEDDED
1137 bool "Embedded system"
1138 select EXPERT
1139 help
1140 This option should be enabled if compiling the kernel for
1141 an embedded system so certain expert options are available
1142 for configuration.
1143
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001144config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001145 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001146 help
1147 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001148
Peter Zijlstra906010b2009-09-21 16:08:49 +02001149config PERF_USE_VMALLOC
1150 bool
1151 help
1152 See tools/perf/design.txt for details
1153
Ingo Molnar57c0c152009-09-21 12:20:38 +02001154menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001155
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001156config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001157 bool "Kernel performance events and counters"
1158 default y if (PROFILING || PERF_COUNTERS)
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001159 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001160 select ANON_INODES
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001161 select IRQ_WORK
Thomas Gleixner0793a612008-12-04 20:12:29 +01001162 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001163 Enable kernel support for various performance events provided
1164 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001165
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001166 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001167 use of generic tracepoints.
1168
1169 Most modern CPUs support performance events via performance
1170 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001171 types of hw events: such as instructions executed, cachemisses
1172 suffered, or branches mis-predicted - without slowing down the
1173 kernel or applications. These registers can also trigger interrupts
1174 when a threshold number of events have passed - and can thus be
1175 used to profile the code that runs on that CPU.
1176
Ingo Molnar57c0c152009-09-21 12:20:38 +02001177 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001178 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001179 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001180 provides per task and per CPU counters, and it provides event
1181 capabilities on top of those.
1182
1183 Say Y if unsure.
1184
Ingo Molnar57c0c152009-09-21 12:20:38 +02001185config PERF_COUNTERS
1186 bool "Kernel performance counters (old config option)"
1187 depends on HAVE_PERF_EVENTS
1188 help
1189 This config has been obsoleted by the PERF_EVENTS
1190 config option - please see that one for details.
1191
1192 It has no effect on the kernel whether you enable
1193 it or not, it is a compatibility placeholder.
1194
1195 Say N if unsure.
1196
Peter Zijlstra906010b2009-09-21 16:08:49 +02001197config DEBUG_PERF_USE_VMALLOC
1198 default n
1199 bool "Debug: use vmalloc to back perf mmap() buffers"
1200 depends on PERF_EVENTS && DEBUG_KERNEL
1201 select PERF_USE_VMALLOC
1202 help
1203 Use vmalloc memory to back perf mmap() buffers.
1204
1205 Mostly useful for debugging the vmalloc code on platforms
1206 that don't require it.
1207
1208 Say N if unsure.
1209
Thomas Gleixner0793a612008-12-04 20:12:29 +01001210endmenu
1211
Christoph Lameterf8891e52006-06-30 01:55:45 -07001212config VM_EVENT_COUNTERS
1213 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001214 bool "Enable VM event counters for /proc/vmstat" if EXPERT
Christoph Lameterf8891e52006-06-30 01:55:45 -07001215 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001216 VM event counters are needed for event counts to be shown.
1217 This option allows the disabling of the VM event counters
David Rientjes6a108a12011-01-20 14:44:16 -08001218 on EXPERT systems. /proc/vmstat will only show page counts
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001219 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001220
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001221config PCI_QUIRKS
1222 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001223 bool "Enable PCI quirk workarounds" if EXPERT
Geert Uytterhoeven61cfc7e2008-10-22 08:53:25 +02001224 depends on PCI
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001225 help
1226 This enables workarounds for various PCI chipset
1227 bugs/quirks. Disable this only if your target machine is
1228 unaffected by PCI quirks.
1229
Christoph Lameter41ecc552007-05-09 02:32:44 -07001230config SLUB_DEBUG
1231 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001232 bool "Enable SLUB debugging support" if EXPERT
Christoph Lameterf6acb632008-04-29 16:16:06 -07001233 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001234 help
1235 SLUB has extensive debug support features. Disabling these can
1236 result in significant savings in code size. This also disables
1237 SLUB sysfs support. /sys/slab will not exist and there will be
1238 no support for cache validation etc.
1239
Randy Dunlapb943c462009-03-10 12:55:46 -07001240config COMPAT_BRK
1241 bool "Disable heap randomization"
1242 default y
1243 help
1244 Randomizing heap placement makes heap exploits harder, but it
1245 also breaks ancient binaries (including anything libc5 based).
1246 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001247 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001248 /proc/sys/kernel/randomize_va_space to 2.
1249
1250 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1251
Christoph Lameter81819f02007-05-06 14:49:36 -07001252choice
1253 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001254 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001255 help
1256 This option allows to select a slab allocator.
1257
1258config SLAB
1259 bool "SLAB"
1260 help
1261 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001262 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001263 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001264
1265config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001266 bool "SLUB (Unqueued Allocator)"
1267 help
1268 SLUB is a slab allocator that minimizes cache line usage
1269 instead of managing queues of cached objects (SLAB approach).
1270 Per cpu caching is realized using slabs of objects instead
1271 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001272 and has enhanced diagnostics. SLUB is the default choice for
1273 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001274
1275config SLOB
David Rientjes6a108a12011-01-20 14:44:16 -08001276 depends on EXPERT
Christoph Lameter81819f02007-05-06 14:49:36 -07001277 bool "SLOB (Simple Allocator)"
1278 help
Matt Mackall37291452008-02-04 22:29:38 -08001279 SLOB replaces the stock allocator with a drastically simpler
1280 allocator. SLOB is generally more space efficient but
1281 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001282
1283endchoice
1284
Jie Zhangea637632009-12-14 18:00:02 -08001285config MMAP_ALLOW_UNINITIALIZED
1286 bool "Allow mmapped anonymous memory to be uninitialized"
David Rientjes6a108a12011-01-20 14:44:16 -08001287 depends on EXPERT && !MMU
Jie Zhangea637632009-12-14 18:00:02 -08001288 default n
1289 help
1290 Normally, and according to the Linux spec, anonymous memory obtained
1291 from mmap() has it's contents cleared before it is passed to
1292 userspace. Enabling this config option allows you to request that
1293 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1294 providing a huge performance boost. If this option is not enabled,
1295 then the flag will be ignored.
1296
1297 This is taken advantage of by uClibc's malloc(), and also by
1298 ELF-FDPIC binfmt's brk and stack allocator.
1299
1300 Because of the obvious security issues, this option should only be
1301 enabled on embedded devices where you control what is run in
1302 userspace. Since that isn't generally a problem on no-MMU systems,
1303 it is normally safe to say Y here.
1304
1305 See Documentation/nommu-mmap.txt for more information.
1306
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001307config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001308 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001309 help
1310 Say Y here to enable the extended profiling support mechanisms used
1311 by profilers such as OProfile.
1312
Ingo Molnar5f87f112008-07-23 14:15:22 +02001313#
1314# Place an empty function call at each tracepoint site. Can be
1315# dynamically changed for a probe function.
1316#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001317config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001318 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001319
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001320source "arch/Kconfig"
1321
Linus Torvalds1da177e2005-04-16 15:20:36 -07001322endmenu # General setup
1323
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001324config HAVE_GENERIC_DMA_COHERENT
1325 bool
1326 default n
1327
Linus Torvalds158a9622008-01-02 13:04:48 -08001328config SLABINFO
1329 bool
1330 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001331 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001332 default y
1333
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001334config RT_MUTEXES
1335 boolean
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001336
Linus Torvalds1da177e2005-04-16 15:20:36 -07001337config BASE_SMALL
1338 int
1339 default 0 if BASE_FULL
1340 default 1 if !BASE_FULL
1341
Jan Engelhardt66da5732007-07-15 23:39:29 -07001342menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001343 bool "Enable loadable module support"
1344 help
1345 Kernel modules are small pieces of compiled code which can
1346 be inserted in the running kernel, rather than being
1347 permanently built into the kernel. You use the "modprobe"
1348 tool to add (and sometimes remove) them. If you say Y here,
1349 many parts of the kernel can be built as modules (by
1350 answering M instead of Y where indicated): this is most
1351 useful for infrequently used options which are not required
1352 for booting. For more information, see the man pages for
1353 modprobe, lsmod, modinfo, insmod and rmmod.
1354
1355 If you say Y here, you will need to run "make
1356 modules_install" to put the modules under /lib/modules/
1357 where modprobe can find them (you may need to be root to do
1358 this).
1359
1360 If unsure, say Y.
1361
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001362if MODULES
1363
Linus Torvalds826e4502008-05-04 17:04:16 -07001364config MODULE_FORCE_LOAD
1365 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001366 default n
1367 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001368 Allow loading of modules without version information (ie. modprobe
1369 --force). Forced module loading sets the 'F' (forced) taint flag and
1370 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001371
Linus Torvalds1da177e2005-04-16 15:20:36 -07001372config MODULE_UNLOAD
1373 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001374 help
1375 Without this option you will not be able to unload any
1376 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001377 anyway), which makes your kernel smaller, faster
1378 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001379
1380config MODULE_FORCE_UNLOAD
1381 bool "Forced module unloading"
1382 depends on MODULE_UNLOAD && EXPERIMENTAL
1383 help
1384 This option allows you to force a module to unload, even if the
1385 kernel believes it is unsafe: the kernel will remove the module
1386 without waiting for anyone to stop using it (using the -f option to
1387 rmmod). This is mainly for kernel developers and desperate users.
1388 If unsure, say N.
1389
Linus Torvalds1da177e2005-04-16 15:20:36 -07001390config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001391 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001392 help
1393 Usually, you have to use modules compiled with your kernel.
1394 Saying Y here makes it sometimes possible to use modules
1395 compiled for different kernels, by adding enough information
1396 to the modules to (hopefully) spot any changes which would
1397 make them incompatible with the kernel you are running. If
1398 unsure, say N.
1399
1400config MODULE_SRCVERSION_ALL
1401 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001402 help
1403 Modules which contain a MODULE_VERSION get an extra "srcversion"
1404 field inserted into their modinfo section, which contains a
1405 sum of the source files which made it. This helps maintainers
1406 see exactly which source was used to build a module (since
1407 others sometimes change the module source without updating
1408 the version). With this option, such a "srcversion" field
1409 will be created for all modules. If unsure, say N.
1410
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001411endif # MODULES
1412
Rusty Russell98a79d62008-12-13 21:19:41 +10301413config INIT_ALL_POSSIBLE
1414 bool
1415 help
1416 Back when each arch used to define their own cpu_online_map and
1417 cpu_possible_map, some of them chose to initialize cpu_possible_map
1418 with all 1s, and others with all 0s. When they were centralised,
1419 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001420 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301421
Linus Torvalds1da177e2005-04-16 15:20:36 -07001422config STOP_MACHINE
1423 bool
1424 default y
1425 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1426 help
1427 Need stop_machine() primitive.
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001428
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001429source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07001430
1431config PREEMPT_NOTIFIERS
1432 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01001433
Steffen Klassert16295be2010-01-06 19:47:10 +11001434config PADATA
1435 depends on SMP
1436 bool
1437
Thomas Gleixner6beb0002009-11-09 15:21:34 +00001438source "kernel/Kconfig.locks"